Even with his Magic Array, Lin Yun could only shorten the long and complicated incantation to 6 seconds, moreover, the area targeted by the spell couldn't be moved once it was cast. During complicated battles, especially against a powerhouse like the Death Knight, standing and casting for six seconds was no different from courting death.
Not to mention the fact that Hellfire had stringent requirements on the density and activity of the fire elements, but the casting location also had to be chosen at the start and couldn't be changed afterwards.
During battles, opponents wouldn't stop in the same place for six seconds to become targets. But the power of hellfire made up for these limitations, making it the most formidable special fire-type magic.
But if an enemy couldn't be hit, then no matter how formidable the spell was, it was useless! By the time the casting was over, the enemy would have already escaped far out of its range.
